Radial firing warhead system and method

ABSTRACT

A warhead system, method and apparatus. A warhead includes a liner having a logitundinal axis that runs down the center of the liner. The liner includes a liner pattern and a liner shape. The liner shape is selected and a radial distance from the longitudinal axis is selected. The liner pattern is warped as a function of the selected distance and the shape of the liner to reduce the effects of spoking in the post-detonation fragmentation pattern at the selected distance. The liner is then formed as a function of the warped liner pattern.

BACKGROUND

A typical fragmentation warhead, upon detonation, produces a radiallyexpanding pattern of fragments. Characteristic of a pattern produced bythis type of warhead is an inconsistent linear grouping of fragmentsotherwise known as “spoking”. Spoking reduces the probability of hit ontarget thus limiting the lethality of the warhead.

What is needed is a system and method for reducing the effects ofspoking in a radial firing warhead.

BRIEF DESCRIPTION OF THE FIGURES

In the drawings, which are not necessarily drawn to scale, like numeralsmay describe similar components in different views. Like numerals havingdifferent letter suffixes may represent different instances of similarcomponents. The drawings illustrate generally, by way of example, butnot by way of limitation, various embodiments discussed in the presentdocument.

FIGS. 1 a, 1 b and 2 illustrate a warhead;

FIGS. 3 a and 3 b illustrate a warhead liner that can be used in thewarhead of FIGS. 1 a, 1 b and 2;

FIG. 4 a illustrates a post-detonation fragmentation pattern;

FIG. 4 b illustrates impact of the fragmentation pattern of FIG. 4 a ona target;

FIGS. 5 and 6 illustrate preformed fragmentation liners;

FIGS. 7 a and 7 b illustrate controlled fragmentation scored liners; and

FIG. 8 illustrates a method of forming a pattern for a warhead.

DETAILED DESCRIPTION

In the following detailed description of example embodiments of theinvention, reference is made to specific examples by way of drawings andillustrations. These examples are described in sufficient detail toenable those skilled in the art to practice the invention, and serve toillustrate how the invention may be applied to various purposes orembodiments. Other embodiments of the invention exist and are within thescope of the invention, and logical, mechanical, electrical, and otherchanges may be made without departing from the subject or scope of thepresent invention. Features or limitations of various embodiments of theinvention described herein, however essential to the example embodimentsin which they are incorporated, do not limit the invention as a whole,and any reference to the invention, its elements, operation, andapplication do not limit the invention as a whole but serve only todefine these example embodiments. The following detailed descriptiondoes not, therefore, limit the scope of the invention, which is definedonly by the appended claims.

A fragmentation warhead is shown in FIGS. 1 a and 1 b. Fragmentationwarhead 100 is a Multiple Explosively Formed Projectile (MEFP) warhead;it includes an approximately cylindrical liner 102 having a longitudinalaxis that runs down the center of the cylinder. Warhead 100 alsoincludes a forward bulkhead 104, an all bulkhead 106, and a detonator108. An explosive (not shown) is deposited within liner 102. Liner 102includes a liner pattern selected to cause the liner to form a pluralityof radially expanding projectiles when the explosive is detonated. Inthe example shown in FIGS. 1 a and 1 b, a liner pattern of hexagonaldimples is used.

An exploded view of fragmentation warhead 100 from FIGS. 1 a and 1 b isshown in FIG. 2. Once again, fragmentation warhead 100 includes anapproximately cylindrical liner 102 having a longitudinal axis that runsdown the center of the cylinder. Warhead 100 also includes a forwardbulkhead 104, an aft bulkhead 106, and a detonator 108. Explosive 112and booster charge 110 are deposited within liner 102 and ignited bydetonator 108. Liner 102 includes a liner pattern selected to cause theliner to form a plurality of radially expanding projectiles when theexplosive is detonated.

As noted above, a typical fragmentation warhead, upon detonation,produces a radially expanding pattern of fragments. One characteristicof such warheads is that they produce a post-detonation fragmentationpattern having an inconsistent linear grouping of fragments, otherwiseknown as “spoking”. Spoking reduces the probability of hit on targetthus limiting the lethality of the warhead.

The warhead of FIG. 1 reduces the effects of spoking. At example linerpattern for warhead 100 is shown in FIGS. 3 a and 3 b. In the exampleshown in FIGS. 3 a and 3 b, the WEI) pattern in cylindrical liner 102 iswarped relative to the longitudinal axis of the cylindrical liner inorder to reduce spoking In the example shown in FIGS. 3 a and 3 b, theliner pattern moves in a spiral at an angle θ from a line on the outsidesurface of the cylindrical liner parallel to the longitudinal axis 120.The liner pattern selected determines the post-detonation fragmentationpattern. In the embodiment shown in FIGS. 3 a and 3 b, the angle θ isapproximately 15 degrees. Other angles can be used as well; the angle θselected determines where you get an optimal post-detonation fragmentdistribution as you move radially out from the longitudinal axis of thecylindrical liner. In one example embodiment, angle θ is selected sothat the liner pattern repeats every fourth row as you move upcylindrical lining 102.

The angle θ can also be measured normal from the longitudinal axis 120as is shown in FIG. 3 b.

The resulting fragmentation pattern post detonation is shown in FIGS. 4a and 4 b, where you can see that the fragmentation pattern 150 has anapproximately uniform distribution with little signs of spoking at theselected distance. An even distribution of fragments enables full lethalpotential of the warhead by maximizing probability of a hit on thetarget 152. It should be noted that as fragment size becomes larger,this approach has even greater impact,

In one embodiment, a liner pattern is selected that repeats a design toform a ring around cylindrical liner 102 and then repeats to form a setof rings moving up cylindrical liner 102. In one example embodiment,each ring is offset radial from its neighbors. In one such embodiment,rings line up every fourth ring.

By warping the warhead liner pattern to compensate for characteristicssuch as spoking, one can achieve a desired post-detonation fragmentationpattern. The MEFP warhead liners described above provide post-detonationfragmentation patterns that have fragments that are approximately thesame quantity and size of the fragments generated by a warhead linerhaving a similar pattern running parallel to longitudinal axis 120. Theprocess of warping the liner pattern described above relies on skewing,or spiraling, of the fragmentation inducing geometry relative to thelongitudinal axis to reduce spoking Application of the spiraling to theliner pattern reduces spoking and improves fragment spatial distributionwithout compromising fragmentation mass and velocity.

The approaches described above can also be used in controlledfragmentation warheads, in warheads having preformed fragments such asball bearings and in multiple shaped charge warheads. Multiple shapedcharge warheads use a similar approach to that described above butdiffer in that the dimpling is designed such that the fragments collapserapidly to form continuously stretching jets, or shaped charge jets. Infragmentation warheads, the warping is applied to the scoring pattern.In warheads with preformed fragments, the warping is realized in thepattern of, e.g., the ball bearings.

These approaches result in improvement in the post-detonationfragmentation pattern without compromising fragment velocity, Thisimproved distribution of fragments enables full lethal potential of thewarhead by maximizing the probability of hit on target. As noted above,this approach can be applied to various types of fragmentation warheadsincluding controlled and preformed. Examples of controlled fragmentationinclude asymmetrical notch and. Multiple Explosively Formed Projectile(MEFP) warheads.

In one example embodiment, for preformed fragmentation warheads, thespiraling is applied to the overall packing of the fragments. In oneexample embodiment, as is shown in FIG. 5, warhead liner 160 includesbearings 162 that spiral up a cylinder in an approximately 15 degreespiral. A potting material holds the fragments in place. In oneembodiment, as is shown in FIG. 6, each warhead liner 160 includes anumber of spirals 164 that are offset as shown.

For controlled fragmentation warheads, the spiraling is applied to theliner pattern as is shown in FIGS. 7 a and 7 b. Several variables guidethe selection of the spiral angle, including stand-off requirements ofthe munition system and warhead characteristics such as liner diameterand individual fragment diameter.

In one embodiment, as is shown in FIG. 8, software is used to model aparticular distribution pattern at a selected distance. At 180, a radialdistance is selected. The radial distance is the distance radially fromthe warhead where the desired distribution pattern is needed. At 182, adesired pattern is selected and, at 184 that selected distributionpattern is mapped back on the cylindrical liner to form the pattern tobe used. Complex distributions can be achieved in this manner.

In one embodiment, a warhead includes an approximately cylindrical linerwith an outside surface and a longitudinal axis that runs down thecenter of the cylinder; a top end-cap attached to the liner; a bottomend-cap attached to the liner; and an explosive deposited inside theliner. The liner includes a pattern, wherein the pattern is selected tocause the liner to form a plurality of radially expanding projectileswhen the explosive is detonated and wherein the pattern includes arepeating pattern which reduces spoking.

In one embodiment, the pattern defines areas that form explosivelyformed projectiles when the explosive is detonated.

In one embodiment, the liner is a controlled fragmentation scored linerscored on the inside with the pattern. In one such embodiment, the lineris scored on the inside with the pattern and wherein the pattern movesin a spiral around the longitudinal axis.

In one embodiment, the liner is a preformed fragmentation liner which iscomposed of discrete fragments imbedded into a potting material tomaintain its form. This preformed fragmentation liner is formed into thepattern, wherein the pattern moves in a spiral around the longitudinalaxis.

In one embodiment, the pattern defines areas that form explosivelyformed projectiles when the explosive is detonated and wherein thepattern repeats at a first angle, wherein the first angle is selectedsuch that the pattern moves in a spiral around the longitudinal axis.

In one embodiment, the pattern repeats at a first angle, wherein thefirst angle is selected such that the pattern moves in a spiral aroundthe longitudinal axis.

In one embodiment, the pattern is selected to provide an approximatelyuniform distribution of fragments at a selected distance radially fromthe cylindrical liner.

In one embodiment, a warhead includes a liner having a longitudinal axisthat runs down the center of the liner; a detonator attached to theliner; a bottom end-cap attached to the liner; and an explosivedeposited inside the liner. The liner includes a pattern, wherein thepattern is selected to cause the liner to forma plurality of radiallyexpanding projectiles when the explosive is detonated and wherein thepattern is selected to reduce spoking.

In one such embodiment, the warhead has a circular cross-section. In onesuch embodiment, the liner includes a repeating pattern which repeats ina spiral around the longitudinal axis of the liner. In one suchembodiment, the pattern is selected to provide an approximately uniformdistribution of fragments at a selected distance radially from thecylindrical liner.

In one such embodiment, the pattern defines areas that form explosivelyformed projectiles when the explosive is detonated. In one suchembodiment, the liner is a preformed fragmentation liner. In one suchembodiment, the liner is a

controlled fragmentation scored liner.

In one embodiment a method of manufacturing a liner for a warheadincludes selecting a liner shape, wherein the liner shape includes alongitudinal axis; creating a fragmentation pattern; selecting adistance radial to the longitudinal axis; warping the fragmentationpattern as a function of the selected distance and the shape of theliner to reduce the effects of spoking at the selected distance; andforming the liner as a function of the warped fragmentation pattern.

In one such embodiment, selecting the liner shape includes selecting oneof a cylinder shape and a tapered cylinder shape. In one suchembodiment, selecting the liner shape includes selecting a cylindershape and wherein warping the fragmentation pattern includes determiningan expected fragmentation pattern expected from detonating a warheadwith a liner having a cylinder shape.

In one such embodiment, selecting the liner shape includes selecting atapered cylinder shape and wherein warping the fragmentation patternincludes determining an expected fragmentation pattern expected fromdetonating a warhead with a liner having a tapered cylinder shape.

Although the example embodiments described above describe liners thatare approximately cylindrical, providing a warp such as a helical twistcould be applied to, for example, a tapered cylinder as well. Inaddition, the mapping software described above can be used to map anydesired distribution pattern on any warhead liner in order to achieve adistribution that approximates the desired distribution.

As noted above, a typical fragmentation warhead, upon detonation,produces a radially expanding pattern of fragments. Characteristic of apattern produced by this type of warhead is an inconsistent lineargrouping of fragments otherwise known as “spoking”. Spoking reduces theprobability of hit on target thus limiting the lethality of the warhead.The application of this invention addresses this problem to produce aneven distribution of fragments. An even distribution of fragmentsenables full lethal potential by maximizing the probability of hit ontarget. The solution described above addresses these issues.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat any arrangement which is calculated to achieve the same purpose maybe substituted for the specific embodiments shown. The invention may beimplemented in various modules and in hardware, software, and variouscombinations thereof, and any combination of the features described inthe examples presented herein is explicitly contemplated as anadditional example embodiment. This application is intended to cover anyadaptations or variations of the example embodiments of the inventiondescribed herein. It is intended that this invention be limited only bythe claims, and the full scope of equivalents thereof.

1. A warhead, comprising: an approximately cylindrical liner having anoutside surface and a longitudinal axis that runs down the center of thecylinder; a forward bulkhead attached to the liner; an aft bulkheadattached to the liner; and an explosive deposited inside the liner;wherein the liner includes a liner pattern, wherein the liner pattern isselected to cause the liner to form a post-detonation fragmentationpattern having a plurality of radially expanding projectiles when theexplosive is detonated; and wherein the pattern includes a repeatingpattern which reduces spoking in the post-detonation fragmentationpattern .
 2. The warhead of claim 1, wherein the pattern defines areasthat form explosively formed projectiles when the explosive isdetonated.
 3. The warhead of claim 1, wherein the liner is a controlledfragmentation scored liner scored on the inside with the pattern.
 4. Thewarhead of claim 1, wherein the liner is a controlled fragmentationscored liner, wherein the liner is scored on the inside with the patternand wherein the pattern moves in a spiral around the longitudinal axis.5. The warhead of claim 1, wherein the liner is a preformedfragmentation liner formed into the pattern, wherein the liner is pottedin a potting material to maintain its form.
 6. The warhead of claim 1,wherein the liner is a preformed fragmentation liner formed into theliner pattern, wherein the liner pattern moves in a spiral around thelongitudinal axis and wherein the liner is potted in a potting materialto maintain its form.
 7. The warhead of claim 1, wherein the linerpattern defines areas that form explosively formed projectiles when theexplosive is detonated and wherein the liner pattern repeats at a firstangle, wherein the first angle is selected to give a nearly uniformdistribution at a predetermined distance radially from the cylindricalliner.
 8. The warhead of claim 1, wherein the liner pattern definesareas that form explosively formed projectiles when the explosive isdetonated and wherein the liner pattern repeats at a first angle,wherein the first angle is selected such that the liner pattern moves ina spiral around the longitudinal axis.
 9. The warhead of claim 1,wherein the liner pattern repeats at a first angle, wherein the firstangle is selected such that the liner pattern moves in a spiral aroundthe longitudinal axis.
 10. The warhead of claim 1, wherein the linerpattern is selected to provide an approximately uniform distribution offragments at a selected distance radially from the cylindrical liner.11-13. (canceled)
 14. The warhead of claim 9, wherein the liner patternis selected to provide an approximately uniform distribution offragments at a selected distance radially from the cylindrical liner.15. The warhead of claim 9, wherein the liner pattern defines areas thatform explosively formed projectiles when the explosive is detonated.16-24. (canceled)
 25. A method of manufacturing a warhead, comprising:forming an approximately cylindrical liner having an outside surface anda longitudinal axis that runs down the center of the cylinder; attachinga forward bulkhead to the liner; attaching an aft bulkhead to the liner;and depositing an explosive inside the liner; wherein forming the linerincludes selecting and applying a liner pattern that forms, when theexplosive is detonated, a post-detonation fragmentation pattern having aplurality of radially expanding projectiles; and wherein the linerpattern includes a repeating pattern which reduces spoking in thepost-detonation fragmentation pattern.
 26. The method of claim 25,wherein selecting a liner pattern includes: selecting a radial distancefrom the longitudinal axis; warping the liner pattern as a function ofthe selected distance and the shape of the liner to reduce the effectsof spoking in the post-detonation fragmentation pattern at the selecteddistance; and forming the liner as a function of the warped linerpattern.
 27. The method of claim 25, wherein selecting the liner patternis includes selecting a spiral that moves at an angle θ from a line onthe outside surface of the cylindrical liner parallel to thelongitudinal axis.
 28. The method of claim 27, wherein the angle θ isapproximately 15 degrees.
 29. The method of claim 25, wherein selectingthe liner pattern includes selecting a pattern having a set of ringswith the longitudinal axis at their center.
 30. The method of claim 25,wherein selecting the liner pattern includes selecting a pattern havinga set of rings with the longitudinal axis at their center, wherein eachring is scored to fragment easier and wherein the scoring of one ring isoffset from an adjacent ring.
 31. A machine readable medium comprising aplurality of instructions that, in response to being executed on acomputing device, cause the computing device to carry out a method, themethod comprising: designing an approximately cylindrical liner havingan outside surface and a longitudinal axis that runs down the center ofthe cylinder, wherein the cyclindrical liner includes a forward bulkheadattachment, an aft bulkhead attachment and a cavity which accepts anexplosive; and selecting and applying a liner pattern to the liner,wherein the liner pattern forms, when the explosive is detonated, apost-detonation fragmentation pattern having a plurality of radiallyexpanding projectiles; and wherein the liner pattern includes arepeating pattern which reduces spoking in the post-detonationfragmentation pattern .
 32. The method of claim 31, wherein selecting aliner pattern includes: selecting a radial distance from thelongitudinal axis; warping the liner pattern as a function of theselected distance and the shape of the liner to reduce the effects ofspoking in the post-detonation fragmentation pattern at the selecteddistance; and forming the liner as a function of the warped linerpattern.
 33. The method of claim 31, wherein selecting the liner patternis includes selecting a spiral that moves at an angle θ from a line onthe outside surface of the cylindrical liner parallel to thelongitudinal axis.
 34. The method of claim 33, wherein the angle θ isapproximately 15 degrees.
 35. The method of claim 31, wherein selectingthe liner pattern includes selecting a pattern having a set of ringswith the longitudinal axis at their center.
 36. The method of claim 31,wherein selecting the liner pattern includes selecting a pattern havinga set of rings with the longitudinal axis at their center, wherein eachring is scored to fragment easier and wherein the scoring of one ring isoffset from an adjacent ring.